Bad day at the dyno-need help

[ellis juan]

My setup is as follows..
76 Corvette
LM4 5.3 aluminum block
T56
LS6 intake
1-3/4" LT headers
4.11gears
HP Tuners
GS392 fuel pump

Took the car to the dyno sunday(I will have the graphs in the next day or so) all 3 pulls made about the same 255whp. This setup should be making around 290-300whp. Didnt even read air/fuel up until 4500 rpm, running super lean. I knew something was up which is why I took it to the dyno. 1st gear just didnt have as much pull as I thought it should, just feels dead. Shift to 2nd and it pulls hard, mainly because it doesnt fall below 4500.

Are the ls6 injectors different from the 5.3? What could be the reason for running so lean? If anything I thought the setup would run rich at first. Im running the 5.3 maf by the way.

[LQ495DCMSS]

LS6 injectors could either be 28.8lb/hr or 26 lb/hr. depends on the part number. Did you adjust the injector tables to reflect the swapped injectors?

[69lt1bird]

Why would you go to the dyno without doing some wideband street tuning first? Waste of money.
Post your tune and the log.

[ellis juan]

Cheap dyno day man..sorry, Iv got 30 bucks to blow..I honestly didnt think the car would be THAT far off. Like I said if anything I thought it would be rich and not lean. I dont have a wideband yet, just havent gotten around to buying one. It runs clean besides me kinda thinking it doesnt feel right accelerating in first. I did not adjust the tables for the different injectors. Here is my tune and a decent log file.

Attachment 18355
Attachment 18356

[69lt1bird]

Well, after a quick look through the tune, I would scrap it and start fresh with a stock tune.
PE table looks bad.
AFR Stoich table hacked.
Injector flow rate table wrong.
Spark tables need work, timing is being pulled by IAT and added by AFR Advance.
CAT is still enabled, I am guessing you don't have catalytic converters
Are you using a electronic throttle? If so, the data being shown in the. PID table is way off.

Not a good tune to start with.
Get your wideband and start fresh.

[gr8vet]

Yea, tune is crap. Id scrap the whole car myself. Did you do this? Jezzzz.

I'll fix it fer ya.

Get me the number off your injectors so I can verify.

Later
tt

[ellis juan]

Here is the stock tune minus turning off vats. The only table I have touched since then(previous tune I posted) is TQ management tables, dtcs, added 3deg timing across the board and the gear change table. I havent touched any fueling tables. or anything else. Kinda weird. I would appreciate you fixin it up!

injector numbers 12561462
Attachment 18366

[Cantalope Kid]

injector numbers 12561462

Here is a start for those with Hp Tuners available...I'm at work so no scanner/editor to get you taken care of yet.

Delphi / Bosch
28 lb / hr Injector
Part Number 12561462 (Bosch # 0 280 155 931) - This is a LS1 factory GM injector.
Static Flow Rate: 28 lb/hr (294cc) @ 43.5PSI (300kPa)
Fan spray pattern for superior atomization.
High pressure capability
High Impedance / High-Z

Update: Disregard above folks. Looks like bad info. from here -->>> http://www.ls1tech.com/forums/ls1-do.../t-447226.html

[SSUte01]

I am not sure where that data comes from, but to the best of my knowledge those injectors (LS6) are rated at 28.8lb/hr @ 4 bar (58psi) not 3 bar (just check a stock LS1/6 tune that has those injectors and that would get you what GM uses at least and IIRC it is about 29lb at zero vacuum. 3 bar would put them closer to LS2 injectors in vicinity of 33lb/hr. What is the IFR set for now - cant view tune right now

[69lt1bird]

258cc @ 3bar
24 lb @ 3bar (43.5)
27 lb @ 4bar (58)
http://www.witchhunter.com/flowdatapix/b0280155931.jpg

[Russ K]

The 5.3 Z (flex fuel) engine has larger injectors, your IFR is correct for the stock injectors.

Russ Kemp